The invention relates to a system for connecting a suppressor to an electrical applicance, according to the preamble to Patent Claim 1. Such a system or such a device is described in German Patent Application P 38 34 626.5 which has not yet been published.
In most cases, electrical appliances must be equipped with a suppressor. Generally, this is a suppressor filter or a suppressor capacitor, and these have to be differently connected.
Suppressor filters are constructed with choke coils for the individual conductors in the mains connection cable. Therefore, for each conductor, two possible electrical connection means have to be provided, namely in each case an input into and an output from the suppressor filter; in the case of an alternating current appliance, therefore, four connections are required as well as a further connection for the earthing lead or safety terminal. All these five electrical connection means must be capable of handling the power of the appliance.
In the case of a suppressor capacitor, only a total of three connections (for N, L and earth) are required, the electrical connection means only having to transmit the interference voltages, which means that they can be much smaller and have a smaller cross-section.
Hitherto, suppressors--e.g. the suppressor according to DE--GM 86 28 761.3--were fitted, wired and connected separately inside the appliances, requiring considerable care, expense and a concomitant amount of time. To change a faulty suppressor the appliance usually had to be opened or partially dismantled, and it is not readily possible to exchange a suppressor capacitor for a suppressor filter or vice versa.
In the device described in the as yet unpublished German Application P 38 34 626.5 mentioned at the outset, there is on the bottom of a cable junction box a fitting to hold a suppressor and alongside the fitting there are the per se conventional screw terminals for the wires of the connecting cable. Integrally formed on these screw terminals or the chambers thereof are respective lateral widened portions, each of which has an upwardly and laterally open insertion slot to hold a contact plate of the filter, each insertion slot having associated with it a spring contact element which is connected to a terminal. Upon insertion of this filter casing, therefore, the wires of the connecting cable are simultaneously connected to the filter.
However, it must always be considered a drawback that, in addition to the per se necessary screw terminals for the wires of the connecting cable, it is also necessary to provide widened portions of the chambers and associated spring contact elements. Apart from that, this connection device is suitable and envisaged for the aforesaid suppressor with the axially extending contact plates.
In contrast, the invention is based on the problem of providing a connection system in which contact elements provided on the suppressor, particularly contact arms, can be directly connected to the screw terminals which are in any event required for connecting the wires of the mains cable, so shortening assembly time and also providing for greater safety; the direct connection method is also intended to enhance suppression efficiency.
The premise adopted in order to resolve this problem is the connection device according to Patent Application P 38 34 626.5 in which the suppressor comprises contact arms which project laterally beyond its contours, there being provided on the bottom of the mains junction box a fitting for holding the suppressor and, alongside the fitting, screw terminals for the wires of the connecting cable. The solution according to the invention resides in that with regard to their angular spacings, length and mounting height, the contact arms are disposed to match the screw terminals so that after the suppressor has been inserted into the fitting, the ends of the contact arms rest on the top of the screw terminals. When tightening up the terminal screws, by which in the past only one end of a conductor (or perhaps a plurality of conductor ends) were connected, according to the invention also the associated contact arm of the suppressor is immediately connected directly to the screw terminal. Preferably, the end of each contact arm has a contact lug/contact plate provided with a pierceable hole or a cut-out for the terminal screw.
In the case of one embodiment, when the suppressor filter is fitted, the contact plate with the pierceable hole comes to rest directly on the back of the screw terminal, whereupon the terminal screw can be inserted through the pierceable hole and screwed up tightly on the screw terminal. Certainly, the back of the terminal screw must be accessible from above, i.e. must have a chamber into which the screw terminal is inserted and which has an appropriate opening in the top. Another embodiment is characterised in that the suppressor is pivotable about its longitudinal axis in the fitting, the contact plate provided with a cut-out being adapted to pivot between the back of the screw terminal and the head of the terminal screw which is at a distance therefrom. For this purpose, the chamber of the screw terminal has a corresponding lateral slot into which the contact plate can pivot.
According to a further development of the invention, the contact arms with the contact lugs are so mounted on the top of a connection cap (moulded from insulating material, e.g. synthetic plastics material) that the inner ends of the contact arms contact the connecting members of the filters and/or coils of the suppressor. This cap has on its underside also two (or even three or more, if desired) mutually concentric circular grooves--according to the diameters of the various filter cases--for optional mounting on the top edge of a filter case. These features are explained in detail in the description of the drawings, in respect of FIGS. 6 and 7.